CQ may refer to:
The CQC-6 (Close Quarters Combat — Six) or Viper Six is a handmade tactical folding knife with a tantō blade manufactured by knifemaker Ernest Emerson.
CQ is a code used by wireless operators, particularly those communicating in Morse code, (— · — · — — · —), but also by voice operators, to make a general call (called a CQ call).
CQD (transmitted in Morse code as ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄) is one of the first distress signals adopted for radio use.
CQ Amateur Radio (also known simply as CQ or CQ magazine, and formerly as CQ: The Radio Amateur's Journal) is a magazine for amateur radio enthusiasts first published in 1945. The English language edition is read worldwide; Spanish language edition is published in Spain with some translations of articles from the English language edition and some original European content.
The Boeing B-17 Flying Fortress is a four-engine heavy bomber developed in the 1930s for the United States Army Air Corps (USAAC).